Assembly comprising a diffuser and a gas generator, airbag module and method for installing an assembly

ABSTRACT

In an assembly (20) of an elongate inflator (10) which has an outer housing (14) with outflow openings (18) spread along the circumference (U) and defining an outflow area (16) and an outflow direction, and of a clamp-type diffusor (22) enclosing the outflow area (16), the diffusor (22) includes a central receiving opening (24) into which the outer housing (14) protrudes so that the diffusor (22) circumferentially encloses an axial portion of the outer housing (14) which comprises the outflow area (16). At the inner side of the diffusor (22) delimiting the receiving opening (24) at least one bearing surface (34) and at least one gas guiding surface (30) are provided, wherein the bearing surface (34) bears directly against the outer housing (14) of the inflator (10) and the gas guiding surface (30) is radially spaced apart from the outer housing (14) while forming at least one collecting chamber (30) into which gas flowing out of the outflow area (16) is flowing. The collecting chamber (32) opens into at least one outlet opening (36) through which gas exits the diffusor (22) in an outlet direction (RD) transversely to the outflow direction out of the inflator (10).

TECHNICAL FIELD

The invention relates to an assembly of an elongate inflator and aclamp-type diffusor enclosing an outflow area of the inflator. Further,the invention relates to an airbag module comprising such assembly andto methods for mounting such assembly.

BACKGROUND

In elongate inflators, also referred to as tubular inflators, theoutflow area usually is formed by a plurality of outflow openingsdistributed over the circumference of an outer housing of the inflator.The outflow openings are frequently provided in a filter housing at anaxial end of the inflator. Therefore, the gas flows out of the inflatorin the radial direction. In order to keep the inflator thrust-neutralupon activation thereof, the outflow openings frequently are distributedevenly around the circumference.

In many airbag modules the inflator is arranged so that its outflow areais located inside the inflatable volume of the airbag. This design isfound, for example, in curtain-type side airbags or else in side airbagswhich are installed in a seat back of a vehicle seat.

The airbag must be protected against the gas flow exiting the inflator.To this end, it is known, for example, to provide a specific fabriclayer which surrounds the outflow area of the inflator in thecircumferential direction and which both protects the airbag fabric anddeflects the gas flow in the axial direction. An axially directedoutflow offers the advantage that the gas can be better distributedwithin the airbag.

Moreover, it is known to provide a so-called gas lance which, as a maincomponent, includes a tube section open at both ends and which isaxially attached to an inflator to transfer the outflowing gas over adistance of several decimeters to an airbag disposed remote from theinflator. Although, in this way, a directed gas flow into the airbag canbe generated, it is not possible, however, to dispose the outflow areaof the inflator directly inside the airbag, thus inevitably causing thedimension of the airbag module to be increased.

SUMMARY

It is the object of the invention to provide an option for guiding thegas flowing out of the inflator into the airbag, while the constructiondimension is small, the options of adaptation to different geometriesare good and the manufacturing costs are low.

This object is achieved by an assembly comprising the features of claim1. The assembly consists of an elongate inflator having an outer housingwith outflow openings distributed along the circumference which definean outflow area and an outflow direction, and of a clamp-type diffusorenclosing the outflow area, with the diffusor including a centralreceiving opening into which the outer housing of the inflator protrudesso that the diffusor circumferentially encloses an axial portion of theouter housing that comprises the outflow area. On the inner side of thediffusor delimiting the receiving opening, at least one bearing surfaceand at least one gas guiding surface are provided, the bearing surfacebearing directly against the outer housing and the gas guiding surfacebeing radially spaced apart from the outer housing while forming atleast one collecting chamber into which gas flowing out of the outflowarea is flowing. The collecting chamber opens into at least one outletopening through which gas exits the diffusor in an outlet directiontransversely to the outflow direction from the inflator.

The diffusor simultaneously deflects the gas flowing out of the inflatorinto one or more desired directions and protects the environment againstdirect contact with the outflowing gas. Since the diffusor directlysurrounds the outflow area of the inflator, it can be manufactured tohave small dimensions.

The diffusor can be easily configured so that substantially the wholegas flowing out of the inflator flows into one or more collectingchambers.

Preferably, the diffusor is a formed sheet ring. For example, it may bematerialized as a punched and bent part. This manufacturing methodpermits to easily design the diffusor for different inflator and airbaggeometries and to adapt it, for example, to an axial length of theoutflow area of the inflator or a diameter of the inflator as well as topredefine the desired number, location, position and/or direction of theoutlet openings. Alternatively, the diffusor can be made of a tubeelement, especially a steel tube.

In order to reduce the space required where possible, the diffusorshould be designed to be so short in the axial direction that itprojects at most insignificantly from the axial end of the inflator andthus the axial length of the assembly corresponds substantially to theaxial length of the inflator.

The diffusor can extend, in the axial direction, completely over theoutflow area of the inflator so that the whole outflowing gas initiallyflows into the diffusor.

In this application, the term of “axial length” or of “axial direction”is always used with reference to the longitudinal axis of the inflator.

The outlet direction from the diffusor extends preferably axially withrespect to the longitudinal axis of the inflator, viz. in parallel tothe longitudinal axis thereof. The gas flowing out of the outflow areaof the inflator is deflected especially about 90° transversely to itsoutflow direction.

Of preference, at least two outlet openings which are oppositelydirected are provided. In this case, the gas exits the diffusor in twodirections being opposed but each facing along the axial direction. Thisenables the gas to be distributed more quickly inside the airbag and cankeep the inflator substantially or even completely thrust-neutral.

The volume of the collecting chamber as well as the surface area of theoutlet openings can be selected so that substantially no excessiveexcess pressure vis-à-vis the gas exiting the outflow area is formed inthe diffusor.

The two outlet openings may be opposed along the axial direction. Thesurface area of the two outlet openings may be selected to be equal ordifferent in size. In general, the selection of the number, the surfacearea and the position of the outlet openings is at the discretion ofthose skilled in the art.

Depending on the geometry of the airbag to be filled, also twooppositely directed outlet openings spaced apart from each other in thecircumferential direction can be provided, for example.

The outlet openings can be easily materialized in the diffusor by thegas guiding surface being located, adjacent to the outlet openings,radially further outward than in the at least one associated collectingchamber remote from the outlet openings. In other words, the collectingchamber widens in the radial direction at the transition to the outletopening so that, especially in a radial section, the outlet openingoccupies a larger surface area than the collecting chamber and the gascan flow out of the diffusor without increased resistance.

In the area of the outlet openings, for example, both the gas guidingsurface and the contact surface may be spaced radially apart from theouter periphery of the inflator so that an opening penetrating in theaxial direction is formed through the entire diffusor and is open atboth ends, wherein the two open ends define the outlet openings.

Generally, the collecting chamber(s) can be delimited via the bearingsurface(s) in the axial direction and/or in the circumferentialdirection, with an appropriate selection of the extension of the bearingsurfaces allowing for any geometry of one or more collecting chambers.Further guiding elements for the outflowing gas are not required. Thebearing surfaces basically may be spaced completely apart from eachother or else may merge into each other in portions.

In one possible embodiment, the diffusor is designed so that at leastone collecting chamber is provided which does not continuously extend inthe circumferential direction and which opens into at least one outletopening at its two circumferential ends. The collecting chamber mayextend, for example, over an angular portion of from about 200° to 350°and especially from 220° to 270°.

Two or more collecting chambers separated from each other in thecircumferential direction may be provided, each opening into at leastone outlet opening. It is also imaginable that one outlet opening isassociated with plural collecting chambers.

In another possible embodiment, a collecting chamber is provided thatopens into an outlet opening at an axial end. In this case, the gas neednot first be guided along the circumferential direction but can bedeflected directly in the axial direction by the gas guiding surface.

For example, the outlet opening may be formed, for example, by a radialgap between the outer housing and the inner side of the diffusor, whichfacilitates fabrication of the diffusor. The radial expansion of thediffusor can be delimited, in this configuration, to the radial distanceof the gas guiding surface from the outer wall of the inflator. Inparticular, the outlet opening may be formed between the inner side ofthe gas guiding surface and the outer contour of the inflator by anaxially opened slit.

The two afore-described embodiments can also be combined, of course, sothat the diffusor includes both at least one collecting chamber openinginto an outlet opening in the circumferential direction and at least onecollecting chamber opening into an outlet opening in the axialdirection.

The at least one bearing surface can be used to divide the gas flowexiting the inflator into at least two partial flows. The extension ofthe bearing surface can help easily define the number of the outflowopenings of the inflator located beneath the gas guiding surface whichin turn determine the proportion of the entire filling gas arriving atthe respective partial flow and being guided via the respective gasguiding surface to one of the outlet openings. Preferably, theindividual partial flows are guided into different collecting chambersand, from there, to different outlet openings.

In one possible embodiment, the bearing surface only extends in thecircumferential direction around the outer housing.

In another possible embodiment, the bearing surface extends helicallyaround the outer housing.

One form of the bearing surface which is especially simple to configureand by which partial gas flows with different gas quantities can beproduced provides that, with a bearing surface peripheral around theentire circumference of the inflator, two first portions extending onlyin the circumferential direction and two second portions extendinginclined to the circumferential direction and to the axial direction areprovided, the second portions joining the first portions. Preferably,the bearing surface separates two collecting chambers separated in theaxial direction and each having at least one separate outlet opening.The selection of the length and the inclination of the second portionsextending inclined to the axial direction determines the number of theoutflow openings which supply the respective partial gas flow with gas.

In another embodiment, plural outlet openings can be arranged to becircumferentially distributed. Preferably, the outlet openings areseparated by separation webs which at least partially form the bearingsurfaces of the diffusor delimiting the collecting chamber in the axialdirection. Those outlet openings arranged to be circumferentiallydistributed which interrupt the bearing surface distributed over thecircumference are arranged especially on the front side of the diffusorand thus, in the mounted state of the diffusor, toward a longitudinalend of the inflator.

The diffusor of the assembly may comprise at least one detent elementfor being attached and fastened to the inflator. Preferably, thediffusor in such embodiment comprises two or more detent elements. Thedetent element is configured to engage in a bead for fastening andfixing the diffusor on the inflator. By locking, the diffusor is fixedon the inflator via a positive connection. The detent elements helpfasten the diffusor to the inflator in a simple manner. In addition, itis still possible to additionally fasten the diffusor to the inflator bypressing or welding.

In one embodiment, the detent element is disposed in connection to abearing surface of the diffusor. Such diffusor having one or more detentelements may preferably be made from spring steel, especially anaustempered spring steel.

Usually, the outflow area is provided at an axial end of the inflator sothat also the diffusor is disposed at an axial end of the inflator.

In one embodiment of the assembly, the outflow area of the inflator maybe divided into at least two zones which are separated from each otherby a separation area of the outer housing without outflow openings. Thezones including the outflow openings are preferably configured as axialzones each having circumferentially distributed outflow openings.

In a typical embodiment, in the assembly a bearing surface of thediffusor is positioned in the separation area between the zones. Thebearing surface positioned in the separation area divides the gasexiting the two zones into two separate partial gas flows. Preferably,the diffusor accordingly has two collecting chambers which are arrangedadjacent to the bearing surface positioned in the separation area, andone collecting chamber at a time collects the gas exiting one of the twozones.

The collecting chamber at the rear in the axial direction in suchembodiment has an outlet opening, for example, that is formed by an openportion in a rearward facing sidewall of the diffusor. A partial gasflow can exit said outlet opening in an outlet direction facing awayfrom the longitudinal end of the inflator.

The collecting chamber at the front in the axial direction in suchembodiment has a circumferentially peripheral outlet opening in the formof a radial gap, for example. A partial gas flow can exit said outletopening in the opposite direction vis-à-vis the partial gas flow exitingthe rear collecting chamber.

The zones of the outflow area of the inflator may exhibit a symmetricspreading of the outflow openings. In this way, the assembly can bedesigned to be thrust-neutral with respect to the gas flowing out of theinflator so that 50% of the gas exit through the outlet opening of thecollecting chamber at the front in the axial direction and 50% of thegas exit through the outlet opening of the collecting chamber at therear in the axial direction.

Alternatively, the zones of the outflow area of the inflator may alsohave a non-symmetric distribution of the outflow openings, thus causingan uneven distribution of the gas flow. By such proportionally unevendistribution of the gas flow, a substantially even filling ofdifferently large airbag chambers disposed at the front and rear sidescan be achieved, for example.

A substantial advantage of such assembly resides in the fact that thediffusor can be designed as a standard component and the percentage ofgas distribution can be easily adapted by adapting the number of theoutflow openings associated with the respective zones in the outflowarea of the inflator.

The above-mentioned object is also achieved by an airbag modulecomprising an airbag and an afore-described assembly in which thediffusor is completely arranged in an inflatable inner volume of theairbag.

In this case, it is not necessary to seal the bearing surfacescompletely against the outer surface of the inflator, as possibleleakage flows exit inside the airbag and thus cannot reach theenvironment. Therefore, complex seals can be dispensed with, whichfurther reduces the manufacturing costs.

For mounting an afore-mentioned assembly, a method comprising thefollowing steps is provided. A one-piece diffusor blank is fabricated ofsheet metal in a punching and bending process, with all bearing surfacesand all gas guiding surfaces being pre-formed. The diffusor blank isbent about the outflow area of the inflator, wherein it adopts the finalshape of the diffusor. Finally, the diffusor blank in portions is fixedto itself so as to circumferentially close the same, with its clampshape being imparted to the diffusor.

Preferably, the diffusor blank is pre-tensioned in the last step and isthen welded to itself. For this purpose, e.g., a laser welding processcan be applied.

The fixation advantageously takes place at an area where the edgeportions of the diffusor blank are superimposed.

As an alternative, for mounting an above-mentioned assembly, a methodcomprising the following steps can be provided. A one-piece diffusor isfabricated of a tube element or of a sheet metal, with all bearingsurfaces and all gas guiding surfaces being pre-formed. The diffusorpre-fabricated in this way is slipped onto the outflow area of theinflator. For fastening the diffusor to the inflator, a bearing surfaceof the diffusor is plastically deformed in the area of a bead of theinflator so that the bearing surface engages at least partially or inportions along the periphery in the bead and a positive connection isestablished. The plastic deformation of the bearing surface in the areaof the bead preferably can be produced by a pressing tool.

In another alternative method for mounting the assembly, the followingsteps can be provided. A one-piece diffusor is fabricated of a closedtube element or of a sheet metal, with all bearing surfaces, all gasguiding surfaces and all detent elements being pre-formed. The diffusoris slipped onto the outflow area of the inflator so that the detentelements engage at least in portions along the circumference in the beadand a positive locking is formed. When the diffusor is slipped on, thebearing surfaces with adjacent detent elements are bending radiallyoutward. Upon reaching the beads of the inflator, the detent elementsengage in the beads of the inflator so that the positivelocking/latching of the diffusor on the inflator can be achieved.

Is not required to directly fasten the diffusor on the outer wall of theinflator by any means other than by clamping and/or pressing, and thusthis is usually not intended but nevertheless possible.

This type of fabrication renders the use of a diffusor according to theinvention independent of the outer contour of the inflator along thelongitudinal axis thereof.

The material preferably used is a sheet steel or a steel tube.Especially in a diffusor comprising a detent element, additionally aspring steel, especially an austempered spring steel, can be used.

BRIEF DESCRIPTION OF THE FIGURES

In the following, the invention will be illustrated in detail by way ofplural embodiments and with reference to the attached drawings, wherein:

FIG. 1 shows a schematic perspective view of a longitudinal end of aninflator of an assembly according to the invention;

FIG. 2 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a firstembodiment;

FIG. 3 shows the diffusor from FIG. 2 in a front view;

FIG. 4 shows an airbag module according to the invention including anassembly from FIG. 2 in a longitudinal sectional view;

FIG. 5 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a secondembodiment;

FIG. 6 shows a schematic perspective view of the diffusor from FIG. 5;

FIG. 7 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a thirdembodiment;

FIG. 8 shows the diffusor from FIG. 7 in a rear view;

FIG. 9 shows a schematic perspective view of a longitudinal end of aninflator of an assembly according to the invention;

FIG. 10 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a fourthembodiment;

FIG. 11 shows a schematic longitudinal sectional view of the assemblyfrom FIG. 10;

FIGS. 12 a) to c) show schematic views of different embodiments of alongitudinal end of an inflator of an assembly according to theinvention;

FIGS. 13 a) to c) show partly cut views of an assembly of an inflatorwith a diffusor according to the invention as set forth in a fifthembodiment;

FIG. 14 shows a schematic perspective view of the diffusor from FIG. 13;

FIG. 15 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a sixthembodiment;

FIG. 16 shows a schematic perspective view of an assembly of an inflatorand a diffusor according to the invention as set forth in a seventhembodiment;

FIGS. 17 a) and b) show enlarged partial views onto a front longitudinalend of the inflator with the diffusor according to FIG. 16 inperspective a) rear and b) front views;

FIG. 18 shows the diffusor from FIG. 16 in a perspective front view;

FIG. 19 shows a first schematic longitudinal section of the assemblyfrom FIG. 16;

FIG. 20 shows a second schematic longitudinal section of the assemblyfrom FIG. 16 during a mounting step of the diffusor; and

FIG. 21 shows the second schematic longitudinal section of the assemblyfrom FIG. 16 after completion of the mounting of the diffusor.

DETAILED DESCRIPTION

FIG. 1 illustrates an elongate inflator 10 that includes, at alongitudinal end 12 of its outer housing 14, an outflow area 16 with aplurality of individual outflow openings 18 distributed over thecircumference. The outflow openings 18 in this case are formed in afilter housing of the inflator 10 which is part of the outer housing 14of the inflator 10.

The outflow openings 18 are evenly distributed along the circumferentialdirection U in this case. At a cap sealing the longitudinal end 12 nooutflow openings 18 are provided. When the inflator 10 is activated, thewhole gas generated flows off through the outflow openings 18 of theoutflow area 16 in an outflow direction RGG extending in the radialdirection r.

In the first embodiment of an assembly 20 illustrated in FIG. 2, theoutflow area 16 of the inflator 10 is surrounded by a clamp-typediffusor 22 in the circumferential direction U.

The diffusor 22 includes a central receiving opening 24 (see FIG. 3)into which and, in the shown case, also through which the outer housing14 of the inflator 10 protrudes. In this embodiment, the longitudinalend 12 of the inflator 10, more exactly speaking the cap thereof havingno outflow openings, extends in the axial direction A (along thelongitudinal axis of the inflator 10) a short distance beyond thediffusor 22. This is also visible in FIG. 4.

Along the axial direction A, the diffusor 22 extends merely over aportion 26 that comprises the outflow area 16 and is only slightly widerthan the outflow area 16 (see e.g., FIG. 4).

A gas guiding surface 30 extending over a large portion of thecircumference of the outflow area 16, here over about 225°, is formed onthe inner side 28 of the receiving opening 24 of the diffusor 22.

The gas guiding surface 30 is spaced apart from the outer housing 14 andthe outflow openings 18 in the radial direction r so that gas exitingthe outflow openings 18 flows into the clearance between the outerhousing 14 of the inflator 10 and the gas guiding surface 30, when theinflator 10 is activated. The space between the gas guiding surface 30and the outer housing 14 thus forms a collecting chamber 32 for the gasflowing out of the inflator 10.

The collecting chamber 32 is delimited, in the axial direction A, by twobearing surfaces 34 that bear directly against the outer housing 14 ofthe inflator 10. In this example, both bearing surfaces 34 extend overthe entire circumference of the inflator 10 so that the collectingchamber 32 is sealed in the axial direction A by the two bearingsurfaces 34.

The bearing surfaces 34 also provide for a connection of the diffusor 22to the inflator 10. Being under mechanical stress, they bear against theouter housing 14 of the inflator 10 and retain the diffusor 22 on theouter housing 14 via a clamping force.

The diffusor 22 has plural outlet openings 36 which arefluid-communicated with the collecting chamber 32 and out of which thegas flowing out of the inflator 10 exits the diffusor 22 and thus theassembly 20.

The collecting chamber 32 at each of its two peripheral ends 47 opensinto two outlet openings 36 opposed in the axial direction A. In theexamples shown here, the surface of each of the outlet openings 36 isperpendicular to the axial direction A so that the gas exits theassembly 20 in an outlet direction RD along the axial direction A.

In this embodiment, a total of four outlet openings 36 are provided twoof which are directed in opposite directions so that the gas flows outalong the axial direction A in two opposite outlet directions RD.Opposite to the outflow direction RGG, the outflowing gas is deflected,in this example, about 90° from the radial direction r to the axialdirection A.

In this example, the surface area of all outlet openings 36 is selectedto be equal. Thus, the assembly 20 is thrust-neutral with respect to thegas flowing out of the inflator 10. The surface area of the outletopenings 36 opposite in the axial direction A alternatively may also beselected to have a different size so that an uneven gas distribution isachieved (not shown).

The outlet openings 36 in this embodiment are formed by the gas guidingsurface 30 in an outlet area 38 having a larger distance in the radialdirection r from the outer housing 14 of the inflator 10 than in thearea of the collecting chamber 32. In the outlet area 38, a sidewall 40connecting the gas guiding surface 30 and the adjacent bearing surface34 is interrupted so that the outlet opening 36 is formed.

In this embodiment, the outlet openings 36 are arranged symmetricallyrelative to each other in both opposite sidewalls 40.

Here, two outlet areas 38 spatially separated from each other and eachhaving two opposite outlet openings 36 are provided which are spacedalong the circumferential direction by about 90° (see FIGS. 2 and 3).

Optionally, between said two outlet areas 38 another small collectingchamber 32 is formed, but it is also possible that the gas guidingsurface 30 there substantially bears against the outer housing 14 of theinflator 10 and covers some of the outflow openings 18, whereappropriate.

When the assembly 20 is installed in an airbag module, the inflator 10is inserted into an airbag 42 so far that the longitudinal end 12 of theinflator 10 including the outflow area 16 and the diffusor 22 iscompletely located inside an inflatable inner volume 44 of the airbag42. This is indicated in FIG. 4.

Therefore, it is not necessary for the bearing surfaces 34 to seal thecollecting chamber 32 gas-tightly to the outside, as the whole gasflowing out of the inflator 10 is released inside the airbag 42.Therefore, small leakage flows can be accepted.

The diffusor 22 is manufactured by forming a sheet strip, for examplemade of sheet steel, into a diffusor blank in a punching and bendingprocess (not shown). In this work step, all gas guiding surfaces 30 andbearing surfaces 34 are pre-formed. Said diffusor blank is bent, inanother forming step, around the outflow area 16 of the inflator 10 inthe circumferential direction U, wherein the bearing surfaces 34 comeinto bearing contact with the outer housing 14 of the inflator 10 andalso the gas guiding surfaces 30 adopt their final positions so that thedesired collecting chamber(s) 32 is/are formed between the gas guidingsurfaces 30 and the outer housing 14.

In an overlapping portion 46 (see FIGS. 5 and 6), portions of thediffusor blank are superimposed in the radial direction r and are incontact with each other. In said overlapping portion 46, the diffusorblank is fastened to itself, for example by a suitable welding processsuch as laser welding. The resulting weld 48 clamps the finisheddiffusor 22 to the inflator 10 under mechanical pretension. The diffusorblank is attached merely to itself by a material bond, but not to theinflator 10 by a material bond.

In addition, the diffusor 22 can be fastened to the inflator 10 by asuitable joining process such as crimping. For this purpose, theinflator 10 may include a bead 60 (see FIG. 4). For connecting thediffusor 22 to the inflator 10, the bearing surface 34 of the diffusoris plastically deformed in the region of the bead 60 so that at leastportions of the bearing surface engage in the bead 60 along thecircumference and a positive locking 62 is formed (see FIG. 6).

Alternatively, the diffusor 22 may be completely pre-formed alreadybefore it is applied to the outflow area 16. Such diffusor 22 canequally be manufactured of a sheet strip by a punching and bendingprocess or of a tube element such as a steel tube. Preferably, suchdiffusor 22 is fastened onto the inflator 10, as afore-described, by asuitable joining process such as through a pressing tool.

FIGS. 5 and 6 illustrate an assembly 20 according to a secondembodiment. Since the individual elements only differ by their shape andposition rather than by their function, the already introduced referencenumerals shall be maintained.

In the second embodiment, the diffusor 22 is configured so that twocollecting chambers 32 are formed which are spaced apart from each otheralong the circumferential direction U and each of which opens into aseparate outlet area 38. Each of the outlet areas has two outletopenings 36 which are arranged at opposed axial ends of the diffusor 22and the surface of which is directed in opposite directions along theaxial direction A. Along the axial direction A, the outlet area 38 iscontinuous and the collecting chamber 32 opens centrally into the outletarea 38. In the circumferential direction U between the two collectingchambers 32 and between the two outlet areas 38, the bearing surface 34bears directly against the outer housing 14 of the inflator 10.

The overlapping portion 46 in this example extends in the region of thetwo outlet areas 38 so that the sheet metal from which the diffusor 22is made in this portion is double-layered and is fixed to each other atan appropriate position, here indicated by the weld 48.

In this embodiment, too, the gas exiting the outflow area 16 of theinflator 10 in the radial direction r is initially deflected by the gasguiding surface 30 about 90° into the collecting chambers 20, in thelatter is guided to the outlet areas 38 where it is deflected about 90°again and is divided into two partial gas flows which, in the shownembodiment, exit the diffusor 22 substantially in equal intensity inopposite directions along the axial direction A. The gas volume in theindividual partial gas flows is defined by the number of the outflowopenings 18 in the region of the individual collecting chambers 32.

The number, the arrangement, the shape and the size of the individualcollecting chambers 32, outlet areas 38 and outlet openings 36 are atthe discretion of those skilled in the art, of course, and may beadapted for the respective inflator 10 and the respective application.In particular, the number, the arrangement, the shape and the size ofthe individual collecting chambers 32, outlet areas 38 and outletopenings 36 may also be configured so that an uneven gas distribution iseffectuated.

FIGS. 7 and 8 illustrate a third embodiment of an assembly 20. Incontrast to the just described embodiment, in the overlapping portion 46the diffusor blank is not superimposed in the radial direction r, buttwo portions of the diffusor blank abut against each other along thecircumferential direction U and are adjacent each other along the axialdirection A and along the radial direction r. As afore-described, thediffusor blank in this portion is fixed to itself, shown here by a weld48.

It is another difference from the just described embodiment that a totalof three collecting chambers 32 a, 32 b are provided each of which opensinto one single outlet opening 36 a, 36 b. FIG. 7 shows the diffusor 22in a front view from the longitudinal end 12 of the inflator 10, whereasFIG. 8 illustrates the diffusor 22 in a rear view.

Two first collecting chambers 32 a are spaced apart from each other inthe circumferential direction U and are shaped mirror-inverted withrespect to a diameter of the inflator 10. The gas guiding surface 30 insaid two first collecting chambers 32 a is shaped such that a respectiverearward directed outlet opening 36 a is formed.

The third collecting chamber 32 b is located along the circumferentialdirection U between the two first described collecting chambers 32 a. Ithas one single outlet opening 36 b formed by a radial gap 50 between thediffusor 22 and the outer housing 14 of the inflator 10 and thus equallyorientated with its surface area perpendicularly to the axial directionA so that gas flows out in an outlet direction RD in parallel to theaxial direction A, however directed forward and thus opposed to the gasexiting the outlet openings 36 a.

The outlet opening 36 b is located at an axial end 51 of the secondcollecting chamber 32 b.

Just as in the other embodiments, the surfaces of the individual outletopenings 36 a, 36 b, optionally 36, as well as the size of thecollecting chambers 32 a, 32 b, optionally 32, are selected such thatthe assembly 20 is substantially thrust-neutral.

Alternatively, also in this case an uneven gas distribution is possibleby adapting the surface areas of the individual outlet openings 36 a, 36b as well as the size of the collecting chambers 32 a, 32 b, the size ofthe collecting chambers 32 a, 32 b being adaptable especially by thelocation of the separation web 33 formed by the bearing surface 34. Suchproportionally uneven division of the gas flow can help obtain, forexample, a substantially even filling of differently large airbagchambers disposed on the front and rear sides.

At the rear axial end of the diffusor 22, a bearing surface 34 extendsover the entire circumference of the inflator 10. A bearing surface 34at the front axial end of the diffusor 22 is interrupted in the area ofthe second collecting chamber 32 b. This portion forms the radial gap50.

In general, here the longitudinal end 12 is considered to be the frontend of the inflator 10. Terms such as “front” and “rear” relate to thisorientation.

FIGS. 10 and 11 show an assembly 20 according to a fourth embodiment.

This diffusor geometry, too, can be manufactured from a strip-shapedsheet or a tube element, such as by a punching and bending process.Alternatively, the diffusor can also be manufactured as a helicallywelded, seamlessly drawn or sheet-drawn component.

In this case, especially an inflator 10 as shown in FIG. 9 can be used.The only difference from the inflator shown in FIG. 1 resides in thefact that in the axial direction A the outflow area 16 is divided intotwo axial zones 52, 54 separated from each other by a separation area ofthe outer housing 14 formed as a strip and having no outflow openings18. Accordingly, especially for an uneven gas distribution, the zones 52and 54 may be provided to exhibit a non-symmetric spreading of theoutflow openings 18.

The diffusor 22 of this embodiment has a central bearing surface 34 apositioned in the separation area between the two zones 52, 54. Thus,the central bearing surface 34 a divides the gas exiting the two zones52, 54 into two separate partial gas flows.

The diffusor has two collecting chambers that are arranged along theaxial direction A adjacent to the bearing surface 34. In line with thejust described embodiment, the reference numerals 32 a, 32 b are usedfor said collecting chambers.

Each of the collecting chambers 32 a, 32 b collects the gas exiting oneof the zones 52, 54.

The rear collecting chamber 32 a in this example includes one singleoutlet opening 36 a which is formed by an open portion of a rearwardfacing sidewall 40 and from which a partial gas flow exits directed inan outlet direction RD away from the longitudinal end 12 of the inflator10.

The front collecting chamber 32 b in this example includes acircumferentially peripheral outlet opening 36 b in the form of a radialgap 50 from which a partial gas flow exits in the opposite direction.This geometry is clearly visible in FIG. 11.

Each of the FIGS. 12 a) to 12 c) illustrates the outer housing 14 of aninflator 10 in which in the axial direction A the outflow area 16 isdivided into two axial zones 52, 54 separated from each other by astrip-shaped separation area 68 of the outer housing 14 without outflowopenings 18.

In each of the FIGS. 12 a) and 12 b), an outer housing 14 of theinflator 10 is illustrated which is provided for an uneven gasdistribution, wherein, for this purpose, the zones 52 and 54 show anon-symmetric spreading of the outflow openings 18. In FIG. 12 a), theoutflow openings 18 are distributed to the zones 52 and 54 such thatabout two thirds of the gas flow exit in the area of the zone 52 andabout one third of the gas flow exits in the zone 54. In FIG. 12 b), theoutflow openings 18 are distributed to the zones 52 and 54 such thatabout one third of the gas flow exits in the area of the zone 52 andabout two thirds of the gas flow exit in the zone 54.

In FIG. 12 c), an outer housing 14 of the inflator 10 is illustratedwhich is provided for an even gas distribution, wherein, for thispurpose, the zones 52 and 54 show a symmetric spreading of the outflowopenings 18 so that about half of the gas flow exits in each of the zone52 and the zone 54.

a. As a matter of course, those skilled in the art can also produceother percentage ratios of the gas flow division by a spreading of theoutflow openings 18 to the zones 52 and 54 adapted to the intendedapplication of the assembly 20.

Each of the FIGS. 13 a) to 13 c) illustrates an assembly according to afifth embodiment, wherein in the outer housing 14 of the inflator 10 ofthe assembly 20, the outflow area 16 is divided in the axial direction Ainto two respective axial zones 52, 54 which are separated from eachother by a strip-shaped separation area 68 of the outer housing 14without outflow openings 18.

Also, the diffusor 22 of this embodiment (see FIG. 14) includes acentral bearing surface 34 a which is positioned in the separation area68 between the two zones 52, 54. The diffusor 22 has two collectingchambers 32 a and 32 b which are arranged along the axial direction Aadjacent to the bearing surface 34 a. Each of the collecting chambers 32a, 32 b collects the gas exiting one of the zones 52, 54. Thus, thecentral bearing surface 34 a divides the gas exiting the two zones 52,54 into two separate partial gas flows.

In FIG. 13 a), the outflow openings 18 are distributed to the zones 52and 54 in such a manner that, in the area of the zone 52, about twothirds of the gas flow exit into the collecting chamber 32 b and, in thezone 54, about one third of the gas flow exits into the collectingchamber 32 a. In FIG. 13 b), the outflow openings 18 are distributed tothe zones 52 and 54 in such a manner that, in the area of the zone 52,about one third of the gas flow exits into the collecting chamber 32 band, in the zone 54, about two thirds of the gas flow exit into thecollecting chamber 32 a. In FIG. 13 c), the outflow openings 18 arespread symmetrically/evenly to the zones 52 and 54 so that about half ofthe gas flow exits in the zone 52 into the collecting chamber 32 b andabout half of the gas flow exits in the zone 54 into the collectingchamber 32 a.

The rear collecting chamber 32 a in this example includes one singleoutlet opening 36 a from which a partial gas flow exits in an outletdirection RD directed away from the longitudinal end 12 of the inflator10. The front collecting chamber 32 a in this example includes an outletopening 36 b in the form of a radial gap 50 from which a partial gasflow exits in the opposite direction. The gap 50 is interrupted, as isevident from FIGS. 13 a) to 13 c), in the shown example in thecircumferential direction by the bearing surface 34 at the longitudinalend 12.

This diffusor geometry, too, can be manufactured from a strip-shapedsheet or a tube element, for example by a punching and bending process.Alternatively, also this diffusor may be manufactured as a helicallywelded, seamlessly drawn or sheet-drawn component.

It is the advantage of such assembly 20 according to the fifthembodiment that the diffusor 22 can be designed as a standard component:An adaptation of the percentage gas distribution that is especiallydependent on the intended application of the assembly 20 can be causedby an adaptation of the outer housing 14 in a simple and inexpensiveway. The adaptation of the outer housing 14 preferably takes place by anadaptation of the number of the outflow openings 18 associated with therespective zones 52 and 54 in the outflow area 16 of the outer housing14 of the inflator 10.

FIG. 15 illustrates a sixth embodiment of an assembly 20. In contrast tothe just described embodiment, the central bearing surface 34 a ishelical so that the axial width of the two collecting chambers 32 a, 32b varies along the circumferential direction U.

The helical shape of the central bearing surface 34 is obtained by saidbearing surface 34 a including two first portions 56 which extend onlyalong the circumferential direction U and which are arranged offsetagainst each other along the axial direction A, as well as two secondportions 58 which extend inclined with respect to the axial direction Aand the circumferential direction U and which interconnect the firstportions 56. This design helps define the size of the individualcollecting chambers 32 a, 32 b that determine the intensity of theindividual partial gas flows. This geometry can be employed both with aninflator according to FIG. 1 and with an inflator according to FIG. 9.

In this embodiment, too, the rear collecting chamber 32 a has a rearwarddirected outlet opening 36 a, whereas the front collecting chamber 32 bincludes a forward directed outlet opening 36 b which is peripheralabout the inflator 10 in the form of a radial gap at the front axial end51 of the collecting chamber 32 b in the circumferential direction U.

FIGS. 16 to 21 illustrate an assembly 20 according to a seventhembodiment. FIG. 16 illustrates an inflator according to FIG. 1 to thelongitudinal end 12 of which a self-locking diffusor 22 is attached.Similar to the first embodiment, the longitudinal end 12 of the inflator10, more exactly speaking the cap thereof having no outflow openings,extends even in said sixth embodiment a short distance beyond thediffusor 22 in the axial direction A. This is clearly evident especiallyin FIGS. 17, 19 and 21.

The self-locking diffusor 22 is preferably made from spring steel. Inthe shown embodiment, the gas guiding surface 30 extends over the entirecircumference. On the front side, the diffusor 22 has plural outletopenings 36 b evenly spread over the circumference U here. The outletopenings 36 b are separated by separation webs 33′ which moreover formthe front bearing surfaces 34 (see FIGS. 17b and 18).

On the rear side, in the shown embodiment, the diffusor 22 includes anoutlet opening 36 a that is formed by an opening in portions in the reararea of the gas guiding surface 30 (see FIGS. 17a and 19). In the shownembodiment, an optional guiding element 64 is connected to the bearingsurface 34 arranged in the area of the outlet opening 36 a. Such guidingelement 64 helps deflect the outlet direction RD of the gas into anoutlet direction RD′ (see FIG. 19).

The rear bearing surface 34 of the diffusor is divided, in thecircumferential direction U, into plural portions by separating recesses66. In the embodiment according to FIGS. 16 to 21, the rear bearingsurface 64 comprises four portions. Detent elements 62 that engage inthe bead 60 of the inflator 10 in a mounted state of the diffusor 22 areconnected to two of said portions of the bearing surface 34 which inthis case are arranged adjacent to the portion of the bearing surface 34in the area of the outlet opening 36 a.

FIGS. 20 and 21 illustrate a longitudinal section across the assembly 20in an x-z plane at different times of the mounting of the diffusor 22and the inflator 10.

FIG. 20 illustrates the assembly 20, while the diffusor 20 is slippedonto the inflator 22. The bearing surfaces 34 including the detentelements 62 are bent outward in the radial direction r when the diffusor22 is slipped on. Said bending-open of the detent elements 62 is enabledespecially by separating recesses 66 in the area of the rear bearingsurface 34.

FIG. 21 illustrates the assembly 20 when the mounting is completed.

Accordingly, it is clearly evident that the detent elements 62 areengaged in the bead 60 of the inflator 10 and the diffusor 22 is thuslocked to the inflator 10 in a simple manner. For fixing the diffusor 22to the inflator 10, moreover the separation webs 33′ forming the frontbearing surfaces 34 may be configured to be bent at least slightlyoutward equally in the radial direction r when the diffusor is mounted.Thus, the separation webs 33′ help generate, due to the inherent tensionof the material in the mounted state, a pressing force directed to thecentral axis of the inflator 10 in the area of the front bearingsurfaces 34. As a matter of course, the diffusor 22 can be additionallyfixed to the inflator 10, apart from self-locking, by pressing orwelding, for example.

All features of the individual embodiments can be combined with eachother or exchanged for each other at the discretion of those skilled inthe art, of course, with the desired application and the geometry of theinflator used having to be considered when selecting the shape of thediffusor.

1-21. (canceled)
 22. An assembly (20) of an elongate inflator (10)having an outer housing (14) with outflow openings (18) distributed atthe circumference (U) and defining an outflow area (16) and an outflowdirection (RGG), and of a clamp-type diffusor (22) enclosing the outflowarea (16), especially made from a formed sheet ring or tube element,wherein the diffusor (22) includes a central receiving opening (24) intowhich the outer housing (14) protrudes so that the diffusor (22)circumferentially encloses an axial portion of the outer housing (14)which comprises the outflow area (16), wherein at the inner side (28) ofthe diffusor (22) delimiting the receiving opening (24) at least onebearing surface (34; 34 a) and at least one gas guiding surface (30) areprovided, wherein the bearing surface (34; 34 a) directly bears againstthe outer housing (14) of the inflator (10), and the gas guiding surface(30) is radially spaced apart from the outer housing (14) while formingat least one collecting chamber (32; 32 a, 32 b) into which gas flowingout of the outflow area (16) is flowing, wherein the collecting chamber(32; 32 a, 32 b) opens into at least one outlet opening (36; 36 a, 36 b)through which gas exits the diffusor (22) in an outlet direction (RD)transversely to the outflow direction (RGG) out of the inflator (10).23. The assembly (20) according to claim 22, wherein the outletdirection (RD) extends axially relating to the longitudinal axis of theinflator (10).
 24. The assembly (20) according to claim 22, whereinthere are provided at least two outlet openings (36; 36 a, 36 b) thatare oppositely directed.
 25. The assembly (20) according to claim 22,wherein two or more oppositely directed outlet openings (36; 36 a, 36 b)are provided which are spaced apart from each other in thecircumferential direction (U).
 26. The assembly (20) according to claim22, wherein, adjacent to the outlet opening (36; 36 a), the gas guidingsurface (30) is located radially further outside than in the at leastone associated collecting chamber (32; 32 a) remote from the outletopening (36; 36 a).
 27. The assembly (20) according to claim 22, whereinthe bearing surface(s) (34; 34 a) delimit(s) the collecting chamber(s)(32; 32 a, 32 b) in the axial direction (A) and/or in thecircumferential direction (U).
 28. The assembly (20) according to claim22, wherein at least one collecting chamber (32; 32 a) is provided whichdoes not continuously extend in the circumferential direction (U) andwhich, at its two circumferential ends (37), opens into at least oneoutlet opening (36; 36 a).
 29. The assembly (20) according to claim 22,wherein two collecting chambers (32; 32 a) are provided each of whichextends along the circumferential direction (U) and each of which opens,at one circumferential end (37), into at least one outlet opening (36;36 a).
 30. The assembly (20) according to claim 22, wherein a collectingchamber (32 b) opening into an outlet opening 36 b at an axial end (51)is provided.
 31. The assembly according to claim 30, wherein the outletopening (36 b) is formed by a radial gap (50) between the outer housing(14) and the inner side of the diffusor (22).
 32. The assembly (20)according to claim 22, wherein the at least one bearing surface (34 a)divides the gas flow exiting the inflator (10) into at least two partialflows, especially wherein the bearing surface (34 a) extends helicallyaround the outer housing (14) or only in the circumferential direction(U) around the outer housing (14).
 33. The assembly (20) according toclaim 22, wherein a bearing surface (34 a) peripheral around the entirecircumference of the inflator (10) is provided which includes two firstportions (56) extending only along the circumferential direction (U) andtwo second portions (58) extending inclined to the circumferentialdirection (U) and to the axial direction (A), the second portions (58)connecting the first portions (56).
 34. The assembly (20) according toclaim 22, wherein the outflow area (16) is provided at a longitudinalend (12) of the inflator (10).
 35. The assembly according to claim 22,wherein the outflow area (16) of the inflator (10) is divided into atleast two zones (52, 54) that are separated from each other by aseparation area (68) of the outer housing (14) without outflow openings(18), wherein preferably a bearing surface (34 a) of the diffusor (22)is positioned in the separation area (68) between the zones (52, 54).36. The assembly according to claim 22, wherein the outlet openings (36b) are spread over the circumference (U) and are separated by separationwebs (33′), wherein the separation webs (33′) at least partially formthe bearing surface(s) (34, 34 a) which delimit(s) the collectingchamber (32) in the axial direction (A), especially toward alongitudinal end (12) of the inflator (10).
 37. The assembly (20)according to claim 22, wherein the diffusor (22) comprises at least onedetent element (62), wherein the detent element (62) can engageespecially in a bead (60) for fastening and fixing the diffusor (22) onthe inflator (10).
 38. The assembly according to claim 37, wherein thediffusor (22) is made from spring steel, especially an austemperedspring steel.
 39. An airbag module comprising an airbag (42) and anassembly (20) according to claim 22, wherein the diffusor (22) isarranged completely in an inflatable inner volume (44) of the airbag(42).
 40. A method for mounting an assembly (20) according to claim 22,comprising the following steps: a one-piece diffusor blank is fabricatedof a sheet metal, especially in a punching and bending process, whereinall bearing surfaces (34; 34 a) and all gas guiding surfaces (30) arepreformed, the diffusor blank is bent around the outflow area (16) ofthe inflator (10), wherein it adopts the final shape of the diffusor(22), and portions of the diffusor blank are fixed to themselves so asto circumferentially close the diffusor blank.
 41. A method for mountingan assembly (20) according to claim 22, comprising the following steps:a one-piece diffusor (22) is fabricated of a one-piece closed tubeelement or of a sheet metal, with all of the bearing surfaces (34; 34 a)and all of the gas guiding surfaces (30) being preformed, the diffusor(22) is slipped onto the outflow area (16) of the inflator, and abearing surface (34) of the diffusor (22) is plastically deformed in thearea of a bead (60) of the inflator, especially by a pressing tool, sothat at least portions of the bearing surface (34) engage in the bead(60) along the circumference (U) and a positive locking (62) is formed.42. A method for mounting an assembly (20) according to claim 22,comprising the following steps: a one-piece diffusor (22) is fabricatedof a closed tube element or of a sheet metal, wherein all of the bearingsurfaces (34; 34 a), all of the gas guiding surfaces (30) and all of thedetent elements (62) are preformed, the diffusor (22) is slipped ontothe outflow area (16) of the inflator (10) so that at least portions ofthe detent elements (62) engage in the bead (60) of the inflator (10)along the circumference (U) and a positive locking is formed.